Research on degradation behavior propagation model based on wear

The failure modes and failure mechanisms of Jet pipe electro-hydraulic servo valve (JPEHSV) have been analyzed, knowing that the weak links were the receiver of fluidic amplifier, edges of spool valve amplifier and radial clearance of the valve core and the valve sleeve. By studying the wear mechanisms of the weak links, effects of geometric size on wear and effects of performance of servo valve on geometry size, we determined that as the distance between nozzle and receiver increases, edge fillet radii increase and radial clearance of the valve core and the valve sleeve increase, due to wear in the work process of JPEHSV. Changing geometric size made the flow gains and the pressure gains of two amplifiers reduce, and leakage increase. At the same time, variations in performance parameters of the two amplifiers result in a reduction of flow gain and pressure gain of the servo valve, again causing leakage to increase. The mapping relationships between wear degradation and performance parameters have been analyzed and a double network structure established. To determine the propagation mechanism from the inherent network structure, statistical properties of the network structure were analyzed with small world network theory, and a degradation behavior propagation model based on the small world clustering is proposed. An Ant Colony optimization algorithm was adopted in order to obtain the degradation propagation path with the strong pervasion ability. Finally, an AMESim simulation model of JPEHSV has been built to verify the validity of the propogation model of wear dependent behavior.